In a Long Term Evolution (LTE) Rel-8 system, a variety of system bandwidths are defined in the specification, as illustrated in FIG. 1, where a channel bandwidth is a total bandwidth occupied for the system, and a transmission bandwidth is an active bandwidth for transmission of a signal and in the unit of a Resource Block (RB) at the physical layer. Taking the downlink as an example, a direct current sub-carrier over which no signal is transmitted is centered in the channel bandwidth.
Six types of bandwidths as depicted in Table 1 are supported in the LTE Rel-8 standard.
TABLE 1Channel bandwidth 1.435101520BWChannel [MHz]Configured615255075100transmissionbandwidth/NRB
For a direct current sub-carrier, the direct current sub-carrier is located at the intersection of two central RBs when there are an even number of RBs, e.g., 6 RBs, 50 RBs, 100 RBs, etc., in the transmission bandwidth; and the direct current sub-carrier is centered in a central RB when there are an odd number of RBs, e.g., 15 RBs, 25 RBs, 75 RBs, etc., in the transmission bandwidth, and since an RB consists of 12 sub-carriers in the LTE system, 6 sub-carriers of the central RB are located respectively on both sides of the direct current sub-carrier.
For an LTE-Advanced system, resources of a plurality of LTE component carriers have to be connected for use to support a larger channel bandwidth, e.g., 100 MHz, etc., than the LTE system, and in particular there are two schemes thereof in one of which a plurality of consecutive LTE component carriers are aggregated to provide the LTE-A with a larger transmission bandwidth and in the other of which a plurality of inconsecutive LTE component carriers are aggregated to provide the LTE-A with a larger transmission bandwidth. FIG. 2 is a schematic diagram of aggregated component carriers in an example of aggregated inconsecutive component carriers.
As preferred in an ongoing study of the standardization organization, it is recognized for a design of a system with aggregation of component carriers to keep a design over each component carrier as consistent with the LTE Rel-8 system as possible to thereby ensure that a user equipment of the LTE Rel-8 system can operate normally over each component carrier.
As established in an ongoing study on a demand of the LTE-A system, aggregation of at most 5 component carriers is supported, and a UE supports concurrent reception/transmission of data over at most 5 component carriers.
At present a method for utilizing discrete frequency-domain resources has been proposed in the industry as illustrated in FIG. 3, where there is a central bandwidth, i.e., a segment B0, which is an Rel-8 compatible frequency-domain resource segment, in a frequency-domain resource section B, and a physical resource of the Rel-8 compatible frequency-domain resource segment can be shared between an LTE Rel-8 UE and an LTE-A UE; and a frequency-domain resource segment on both sides thereof, i.e., a segment B-B0, is a non-backward compatible frequency-domain resource segment with a physical resource which can consist of consecutive frequency-domain resources or a plurality of inconsecutive frequency-domain resources. In this method, the several bandwidth values presented in Table 1 are accommodated by the extended channel bandwidth, i.e., the segment B.
In the foregoing carrier resource extension solution, the Rel-8 compatible frequency-domain resource segment is extended, and there remains an issue to be addressed of how to enable an LTE-A user equipment to normally access and use physical resources of a Rel-8 compatible frequency-domain resource segment and a non-backward compatible frequency-domain resource segment by using the extended resource.